1 files changed, 110 insertions, 13 deletions

diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
index 16cf2bd2d0..5b0477aabe 100644
--- a/activerecord/test/cases/query_cache_test.rb
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -10,13 +10,34 @@ class QueryCacheTest < ActiveRecord::TestCase
 
   fixtures :tasks, :topics, :categories, :posts, :categories_posts
 
-  teardown do
+  class ShouldNotHaveExceptionsLogger < ActiveRecord::LogSubscriber
+    attr_reader :logger
+
+    def initialize
+      super
+      @logger = ::Logger.new File::NULL
+      @exception = false
+    end
+
+    def exception?
+      @exception
+    end
+
+    def sql(event)
+      super
+    rescue
+      @exception = true
+    end
+  end
+
+  def teardown
     Task.connection.clear_query_cache
     ActiveRecord::Base.connection.disable_query_cache!
+    super
   end
 
   def test_exceptional_middleware_clears_and_disables_cache_on_error
-    assert !ActiveRecord::Base.connection.query_cache_enabled, "cache off"
+    assert_cache :off
 
     mw = middleware { |env|
       Task.find 1
@@ -26,19 +47,66 @@ class QueryCacheTest < ActiveRecord::TestCase
     }
     assert_raises(RuntimeError) { mw.call({}) }
 
-    assert_equal 0, ActiveRecord::Base.connection.query_cache.length
-    assert !ActiveRecord::Base.connection.query_cache_enabled, "cache off"
+    assert_cache :off
   end
 
-  def test_exceptional_middleware_leaves_enabled_cache_alone
-    ActiveRecord::Base.connection.enable_query_cache!
+  def test_query_cache_across_threads
+    ActiveRecord::Base.connection_pool.connections.each do |conn|
+      assert_cache :off, conn
+    end
 
-    mw = middleware { |env|
-      raise "lol borked"
-    }
-    assert_raises(RuntimeError) { mw.call({}) }
+    assert !ActiveRecord::Base.connection.nil?
+    assert_cache :off
+
+    middleware {
+      assert_cache :clean
+
+      Task.find 1
+      assert_cache :dirty
+
+      thread_1_connection = ActiveRecord::Base.connection
+      ActiveRecord::Base.clear_active_connections!
+      assert_cache :off, thread_1_connection
+
+      started = Concurrent::Event.new
+      checked = Concurrent::Event.new
+
+      thread_2_connection = nil
+      thread = Thread.new {
+        thread_2_connection = ActiveRecord::Base.connection
+
+        assert_equal thread_2_connection, thread_1_connection
+        assert_cache :off
 
-    assert ActiveRecord::Base.connection.query_cache_enabled, "cache on"
+        middleware {
+          assert_cache :clean
+
+          Task.find 1
+          assert_cache :dirty
+
+          started.set
+          checked.wait
+
+          ActiveRecord::Base.clear_active_connections!
+        }.call({})
+      }
+
+      started.wait
+
+      thread_1_connection = ActiveRecord::Base.connection
+      assert_not_equal thread_1_connection, thread_2_connection
+      assert_cache :dirty, thread_2_connection
+      checked.set
+      thread.join
+
+      assert_cache :off, thread_2_connection
+    }.call({})
+
+    ActiveRecord::Base.connection_pool.connections.each do |conn|
+      assert_cache :off, conn
+    end
+  ensure
+    ActiveRecord::Base.clear_all_connections!
   end
 
   def test_middleware_delegates
@@ -62,10 +130,10 @@ class QueryCacheTest < ActiveRecord::TestCase
   end
 
   def test_cache_enabled_during_call
-    assert !ActiveRecord::Base.connection.query_cache_enabled, "cache off"
+    assert_cache :off
 
     mw = middleware { |env|
-      assert ActiveRecord::Base.connection.query_cache_enabled, "cache on"
+      assert_cache :clean
       [200, {}, nil]
     }
     mw.call({})
@@ -121,6 +189,19 @@ class QueryCacheTest < ActiveRecord::TestCase
     end
   end
 
+  def test_cache_does_not_raise_exceptions
+    logger = ShouldNotHaveExceptionsLogger.new
+    subscriber = ActiveSupport::Notifications.subscribe "sql.active_record", logger
+
+    ActiveRecord::Base.cache do
+      assert_queries(1) { Task.find(1); Task.find(1) }
+    end
+
+    assert_not_predicate logger, :exception?
+  ensure
+    ActiveSupport::Notifications.unsubscribe subscriber
+  end
+
   def test_cache_is_flat
     Task.cache do
       assert_queries(1) { Topic.find(1); Topic.find(1); }
@@ -238,6 +319,22 @@ class QueryCacheTest < ActiveRecord::TestCase
       ActiveRecord::QueryCache.install_executor_hooks executor
       lambda { |env| executor.wrap { app.call(env) } }
     end
+
+    def assert_cache(state, connection = ActiveRecord::Base.connection)
+      case state
+      when :off
+        assert !connection.query_cache_enabled, "cache should be off"
+        assert connection.query_cache.empty?, "cache should be empty"
+      when :clean
+        assert connection.query_cache_enabled, "cache should be on"
+        assert connection.query_cache.empty?, "cache should be empty"
+      when :dirty
+        assert connection.query_cache_enabled, "cache should be on"
+        assert !connection.query_cache.empty?, "cache should be dirty"
+      else
+        raise "unknown state"
+      end
+    end
 end
 
 class QueryCacheExpiryTest < ActiveRecord::TestCase